The substrates consist of a core of aluminum oxide or aluminum nitride having coefficients of expansion of 7-8 ppm/K and approx. 4 ppm/K. The substrate can also be a purely ceramic solution in the form of thick-film hybrid supports from aluminum oxide or aluminum nitride having metallized or placed-on conductor tracks. Direct mounting of one or more semiconductors on a metallic lead frame as circuit support can also take place. US 2004-026778 A1 shows the direct mounting of the semiconductor on sections of the lead frame without insulating substrate.
The substrates consist of a core of aluminum oxide or aluminum nitride having coefficients of expansion of 7-8 ppm/K and approx. 4 ppm/K. The substrate can also be a purely ceramic solution in the form of thick-film hybrid supports from aluminum oxide or aluminum nitride having metallized or placed-on conductor tracks. Direct mounting of one or more semiconductors on a metallic lead frame as circuit support can also take place. US 2004-0026778 shows the direct mounting of the semiconductor on sections of the lead frame without insulating substrate.
In the case of a dynamic heat flow, the heat sink plate provides optimum energy buffering with the heat capacity of the selected material (preferably copper). In particular in the case of pulsed operation of the circuit, the heat sink plate reduces the dynamic thermal resistance (Zth). In the stationary case of a heat flow through power loss of these semiconductors, on the other hand the heat-spreading function is of importance. Here, the thermal conductivity of the heat spreading plate is decisive and its dimension that is increased relative to the substrate. This leads to an advantageous thermal resistance (Rth).
In the case of a dynamic heat flow, the heat sink plate provides optimum energy buffering with the heat capacity of the selected material (preferably copper). In particular in the case of pulsed operation of the circuit, the heat sink plate reduces the dynamic thermal resistance (Zth). In the stationary case of a heat flow through power loss of these semiconductors, on the other hand the heat-spreading function is of importance. Here, the thermal conductivity of the heat spreading plate is improved and its dimensions are increased relative to the substrate. This leads to an advantageous thermal resistance (Rth).
Some products also surround, in addition to the substrate unit, a mounted heat sink plate, e.g. DIP-IPM by Mitsubishi (“A New Version Intelligent Power Module for High Performance Motor Control”; M. Iwasaki et. al.; Power Semiconductor Device Division, Mitsubishi, Japan)